A majority of automotive gauge mechanisms presently used in instrument panels are air core gauge designs. These are typically attached to the back side of a transparent face plate comprising a light pipe with an applique placed on the front side. The graphics on the applique are illuminated for night visibility by placing miniature incandescent light bulbs in the rear of the instrument panel where electrical connections are also made to the gauges. The gauge pointers are molded in a clear plastic material with one or more surfaces inclined to effect internal reflection of light from the hub of the pointer to the tip. The clear plastic light pipe has molded-in extension arms that angle down to pick up light from the rear mounted light bulbs. Light travels through the light pipe to a hole surrounding each pointer hub where it enters the bottom of the pointer. Since the light intensity exiting the light pipe varies around the pointer hole, the pointer lighting is often not consistent as the pointer travels through its angular span.
In such gauges the pointers are mounted on metal spindles and are installed by forcing them down onto the spindles to a fixed height or maximum load. Loads, heights and angular position must be monitored and controlled. Robots and vision systems are used to accommodate this tedious and time consuming assembly/calibration procedure.